1. Field of the Invention
The present invention relates to a perfluoroalkyleneethertriazine oligomer and a process for producing the same, and more particularly an oily perfluoroalkyleneethertriazine oligomer useful as an effective oxidation stabilizer for greases, vacuum pump oils, etc. and a process for producing the same.
2. Description of the Prior Art
Liquid perfluoropolyether has a good resistance to heat and oxidation, and also has good lubricability and non-flammability. However, it undergoes a thermal oxidation-type decomposition at a temperature of 250.degree. C. or higher, where the decomposition is accelerated in the presence of some metal or oxide thereof, and the resulting decomposition product gives rise to metal corrosion.
The resistance of liquid perfluoropolyether to oxidation in the presence of such a metal at a high temperature can be increased with an additive capable of inhibiting progress of metal corrosion process. It is also known that a good result can be obtained by using an aromatic phosphine and a phosphorus-containing triazine as oxidation-resistant, corrosion-resistant additives. However, these additives still have drawbacks, i.e. a relatively large volatility at a high temperature and a low solubility in perfluoropolyether at room temperature or a lower temperature.
Another class of liquids particularly stable for the thermal oxidation includes a liquid perfluorotriazine. A fluorine-containing, symmetric triazine has a high stability against the thermal oxidation even at 343.degree. C., but undergoes complete evaporation at 204.degree. C. over 6.5 hours due to the low molecular weight. It is also known that .alpha.,.omega.-di(symmetric triazinyl)perfluoroalkanes having various structures have a good stability against the thermal oxidation, but undergo considerable evaporation at a higher temperature than 200.degree. C. also due to a relatively low molecular weights, and thus have not yet been utilized as a lubricant additive or in other applications.